With the development of integrated circuit manufacturing technology and the scale-down of critical dimensions, some new material and new technology are introduced to the integrated circuit manufacturing technology to meet the requirements of the overall function, so that the accuracy of the connection between such different structures is very important.
When the manufacturing technology is 65 nanometers or less, the slight misalign of alignment between the contact hole and the poly-silicon gate will cause the failure of the overall performance of the device; The present method of detecting the misalign between the two structures (contact hole and the poly-silicon gate) is mainly optical method, while such optical method will limited by resolution size. So it cannot meet the requirement of precise process control when the device size becomes smaller.
FIG. 1 is the structure diagram of defects under the electron microscope after the structure of the front-end device is formed; as shown in FIG. 1, the contact hole 11 is connected to the gate 12 and the active area because there is a certain misalign between the contact hole 11 and the poly-silicon gate 12 in the area 14, which will result in the failure of the performance of the entire device structure 1, thereby affect the yield of the product.